21859138 has 8 divisors (see below), whose sum is σ = 37472832. Its totient is φ = 9368196.

The previous prime is 21859133. The next prime is 21859141. The reversal of 21859138 is 83195812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21859097 and 21859106.

It is not an unprimeable number, because it can be changed into a prime (21859133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 780670 + ... + 780697.

It is an arithmetic number, because the mean of its divisors is an integer number (4684104).

Almost surely, 2^21859138 is an apocalyptic number.

21859138 is a deficient number, since it is larger than the sum of its proper divisors (15613694).

21859138 is a wasteful number, since it uses less digits than its factorization.

21859138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1561376.

The product of its digits is 17280, while the sum is 37.

The square root of 21859138 is about 4675.3757068283. The cubic root of 21859138 is about 279.6046205309.

The spelling of 21859138 in words is "twenty-one million, eight hundred fifty-nine thousand, one hundred thirty-eight".